page_title: History of photographic lens design
section_title: Asymmetric double Gauss
hierarchical_section_title: History of photographic lens design / Asymmetric double Gauss
caption_attribution_description: English: Derived from File:DoubleGauss1text.svg
context_page_description: The invention of the camera in the early 19th century led to an array of lens designs intended for photography. The problems of photographic lens design, creating a lens for a task that would cover a large, flat image plane, were well known even before the invention of photography due to the development of lenses to work with the focal plane of the camera obscura.
context_section_description: In 1817 Carl Friedrich Gauss improved the Fraunhofer telescope objective by adding a meniscus lens to its single convex and concave lens design. Alvan Clark further refined the design in 1888 by taking two of these lenses and placing them back to back. The lens was named in honour of Gauss. The current design can be traced back to 1895, when Paul Rudolph of Carl Zeiss Jena used cemented doublets as the central lenses to correct for chromatic aberration.
  Later the design was developed with additional glasses to give high-performance lenses of wide aperture. The main development was due to Taylor Hobson in the 1920s, resulting in the f/2.0 Opic and later the Speed Panchro designs, which were licensed to various other manufacturers. The design forms the basis for many camera lenses in use today, especially the wide-aperture standard lenses used on 35 mm and other small-format cameras. It can offer good results up to f/1.4 with a wide field of view, and has sometimes been made at f/1.0.
  The design is presently used in inexpensive-but-high-quality fast lenses such as the Canon EF 50mm f/1.8  and Nikon 50 mm f/1.8D AF Nikkor. It is also used as the basis for faster designs, with elements added, such as a seventh element as in both Canon and Nikon's 50 mm f/1.4 offerings or an aspherical seventh element in Canon's 50 mm f/1.2. The design appears in other applications where a simple fast normal lens is required (~53° diagonal) such as in projectors.
caption: Development of the Double Gauss
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